1. Field of the Invention
The present invention relates to an electro-luminescence display, and more particularly, to an electro-luminescence display with an array of electro-luminescence diodes and a method for driving the same.
2. Discussion of the Related Art
Flat panel displays include liquid crystal displays, electro-luminescence displays, and plasma display panels. Flat panel displays are slim and light, and it is easy to manufacture flat panel displays with a large screen size. Therefore, flat panel displays are widely used for computer systems, television sets, and mobile communication devices in replace of cathode ray tubes. Electro-luminescence displays are widely used because they have a wide viewing angle and do not require an additional light source.
An electro-luminescence display includes a plurality of electro-luminescence pixels arranged in the form of an active matrix. Each electro-luminescence pixel emits light according to the voltage or current level of a pixel data signal. To respond to the pixel data signal, each electro-luminescence pixel includes an electro-luminescence diode ELD and a first thin film transistor MT1 that are connected in series between first and second voltage supply lines VDD and VSS, as illustrated in FIG. 1. The first thin film transistor MT1 is used to adjust an amount of current supplied from the first voltage supply line VDD to the electro-luminescence diode ELD in response to a voltage level at a control node CN. The electro-luminescence diode ELD displays a dot of an image by emitting light in proportion to an amount of current supplied from the first voltage supply line VDD.
Referring to FIG. 1, the electro-luminescence pixel further includes a second thin film transistor MT2 connected to a gate line GL, a data line DL and the control node CN, and a storage capacitor Cst connected between the control node CN and the second voltage supply line VSS. The second thin film transistor MT2 is turned on in response to a gate signal from the gate line GL to transmit a pixel data signal from the data line DL to the control node CN. The storage capacitor Cst is used to maintain the voltage level of the pixel data signal supplied to the control node CN. Therefore, the voltage level of the storage capacitor Cst is renewed every time the second thin film transistor MT2 is turned on. Due to the storage capacitor Cst, the first thin film transistor MT1 can continuously operate to display a dot of an image for a predetermined time.
As explained above, in the electro-luminescence pixel of the related art, the first thin film transistor MT1 continuously operates to control the amount of current applied to the electro-luminescence diode ELD during a period when the ELD displays a dot of an image. This continuous operation of the first thin film transistor MT1 results in stresses on the first thin film transistor MT1, thereby damaging the first thin film transistor MT1. In this case, the luminous output of the electro-luminescence diode ELD, which is proportional to the amount of current applied to the electro-luminescence diode ELD, may not correspond to the pixel data signal. As a result, a residual image may be present on the electro-luminescence display.
Moreover, the second thin film transistor MT2 may also be damaged by the continuous operation. Thus the life spans of the first and second thin film transistors MT1 and MT2 and the electro-luminescence display may decrease.